The invention relates in general to furnaces and in particular to a new and useful incinerator plant for waste materials, comprising a horizontal rotating combustion chamber, a vertical lined secondary combustion chamber, and a following waste heat boiler.
Plants for the incineration of waste materials, e.g. special refuse, are known. The waste brought in is supplied via charging and proportioning devices to a rotary tube furnace, in which the introduced materials are burned, depending on their type, at temperatures between 900.degree. and 1300.degree. C. At the end of the rotary tube furnace, the slag is discharged downwardly. For complete combustion the flue gases forming during combustion get into a secondary combustion chamber, in which they are held at a temperature between 900.degree. and 1400.degree. C. Downstream of the secondary chamber a waste heat boiler is mounted, to which the almost homogeneous gas mixture from the secondary combustion chamber is supplied at about 1400.degree. C. Here the gases are cooled to about 300.degree. C., and with the removed heat steam is produced. The slag and ash from the rotary tube furnace and the secondary combustion chamber are taken up by a wet slag remover disposed under the secondary combustion chamber. As a rule, an electrofilter and a wet scrubber complete the waste incinerator plant.
Industrial production, increasing due to the continually growing world population, naturally also creates increasing amounts of industrial waste. Carrying these waste materials to dumps is highly problematical, as this may contaminate the ground water. Besides, the volume of waste to be disposed of is usually so great that the dump area is insufficient. To dispose of these industrial waste materials without danger to the environment, plants for the incineration of the special refuse are set up in chemical plants, in communities, etc. By combustion of the wastes at a high temperature, the dangerous chemicals are transformed into flue gas and ash. The purified gases can then be emitted into the atmosphere without risk and the ash can be dumped without a problem.
There are necessarily limits to the erection of waste incinerator plants and to the development of installation of increasing size. Thus, the size in which in which rotary tube furnaces and waste heat boilers can be built is limited. The refractory lining and the deformability of the rotary tube jacket set limits as to the diameter and length of the furnace. For waste heat boilers, maintaining the cleaning of the boiler and the water circulation demand a limitation in size.
An incinerator plant of the described kind and of the state of the art has reached its maximum at a waste throughput of about 100,000 tons per year in 24-hour operation.
From "VGB Kraftwerkstechnik"64 (1984), p. 1015-1019, an industrial refuse elimination plant is known in which, to bring about as high as possible an availability of the entire plant, two thermal treatment lines working independently of each other were set up.
In German AS No. 23 27 795, a refuse incinerator plant is described where several incinerator furnaces are connected via closable flue gas lines to several steam generators. Named as prior art in this publication are a grate furnace for refuse incineration with secondary combustion chamber, heat exchanger and waste gas dust removal system as a separate unit. Further, reference is made to a refuse incinerator plant in which a waste heat boiler is arranged behind a rotary drum. According to German AS No. 23 27 795, cf. the patent figure, the two steam generators are followed by a common dust removal system for the flue gas and a smokestack. Further, it is stated that it is possible to correlate several incinerator furnaces to one steam generator.